Processes Flashcards
(27 cards)
condensation
mol of water removed to create bond
hydrolysis mol water added
mol water added to break bond
how is water formed [2]
- two covalent bonds between 2 hydrogen and 1 oxygen
- oxygen slightly electronegative causing h+ t attract to it and share electron from valence shell
how are peptide bonds formed?
condensation - OH lost from carboxyl group and H from amide group
How to immobilise an enzyme [2]
attach the enzyme to an insoluble, inert material.
which forms a gel capsule around them in place during a reaction
outline cell signalling [3]
- chemical released by sender cell
- sent through bloodstream to find target cell where it binds to external complementary receptor
- triggers reaction within cell creating a response
outline active transport mechanism [4]
- requires ATP
- Protein changes shape around the molecule
- molecule moved against concentration gradient
- protein has a specific shape for certain molecules
complementary base pairs [2]
G & C - 3 H bonds
A & T/U - 2 H bonds
purines (double ring)
A & G
pyrimdines (single ring)
C, T, U
when does DNA replication happen?
during s phase of interphase
outline DNA replication [3]
- DNA helicase unwinds dna strands by breaking h bonds, leaving 2 templates
- free nucleotides in nuclear sap attach to exposed bases via complementary base pairing
- Dna polymerase joins adjacent nucleotides on a new strand in a 5’ to 3’ direction via condensation reactions to form phosphodiester bonds
What does DNA ligase do? [2]
- for the lagging strand (3’ to 5’) which is diconintuously replicated
- DNA ligase catalysis the formation of phosphodiester bonds between the short nucleotide sequences formed
where does transcription occur
in the nucleus
purpose of transcription
to produce mRNA to send out of the cell
outline transcription process [5]
- DNA helicase unwinds dna strands, breaking h bonds.
- RNA polymerase binds to promotor region on a gene
- free RNA nucleotides align next to theit complementary bases
- RNA polymerase joins adjacent RNA nucleotides forming phosphodiester bonds
- RNA polymerase reaches stop codon and detaches. mRNA complete
what happens after transcription? [2]
- splicing removes introns from pre mRNA in eukaryotic cells leaving exons only
- mRNA moves out of the nuclear pore and attaches to ribosome
what is translation
how proteins are formed by ribosomes
outline translation [5]
- mRNA attaches in groove between subunits of ribosome
- ribosome moves along mRNA until start codon is reached
- amino acid-tRNA complex anticodon attaches to complementary codon via complementary base pairing
- peptide bond forms between adjacent amino acids
- ribosome moves along one codon and release empty tRNA. process continues to form polypeptides until stop codon is reached
describe the apoplastic pathway [2]
- water moves through intercellular spaces between cellulose and molecules in the cell wall
- until it reaches the casparian strip where it’s forced through the symplastic pathway
describe the symplastic pathway [3]
- requires ATP to activley transport water into cells to start
- water enters cytoplasm through plasma membrane
- moves between adjacent cells via plasmodesmata
ouline translocation [5]
- companion cells activley transport h+ into surround tissue creating a concentration gradient
- h+ flows down thei conc gradient via co transporter along with sucrose
- sucrose builds up in companion cell and diffues into sieve tube elements via plasmodesmata
- this lowers water potential causing water to move in from xylem
- assimilates move along sieve tube towards areas of lower hyrostatic pressure where sucrose diffuses into surround cells where needed
how is tissue fluid formed? [2]
- blood pumped through smaller and smaller vessels so hydrostatic pressures becomes higher than oncotic pressure
- so fluid moves out capillaries, it excahnges substances with cells
cardic diastole [4]
- heart relaxed
- blood into atria - opens AV valves
- allows blood into ventricles
- ventricle pressure higher than artery pressure to semilunar valves closed
